Look at the sniper pic in this article. Was this in alpha Halo 4 or something??
http://bitmob.com/articles/halo-4-minor-multiplayer-annoyances
Yes, that was the early version of the UNSC Sniper. It was used during the E3 build.
That’s what 343 was originally going to use as the UNSC Sniper, but too many people complained that the scope looked awkward so they changed it back to what it usually looked like.
The picture was taken during the MLG event where people got to play an Alpha or Beta build of Halo 4, so yes, that Sniper Rifle was the not the finalized version.